1. Field of the Invention
This invention relates to a pin for fixing to each other the laminate layers having compressibility and elasticity. More particularly, the invention relates to a pin for fixing the innermost ceramic fiber layer to other outer wall side ceramic fiber layers or a plurality of such layers lining the wall of a furnace.
2. Description of the Prior Art
Hitherto, in case of lining a furnace by laminating ceramic fiber layers at a inner side of an outer wall of the furnace, it has been required to support the ceramic fiber layers to a casing of the furnace by use of some supporting means. The method has been employed in the conventional furnace in which the ceramic fiber layers have been supported to the casing by a metallic pin welded to the casing. In this method, the allowable temperature of the furnace has been limited by the endurable temperature of the metallic pin, because the end portion of the pin at the inner side of the furnace has been oxidized by exposure to the high temperature environment. In case of using the pin in the environment above the allowable temperature, the method has been known in which a metallic pin having a heat resistant ceramic pin-like member connected to the metallic pin at the end potion thereof.
For instance, as illustrated in FIG. 1, the laminate of ceramic fiber layers 6 is pressed against any one of the fixing means each comprising a metallic pin-like fixing member 2 welded to the casing 1 and another pin-shaped member 4 having a tapered end 4a and joined to said member 2, or the fixing means each comprising a pipe-like member 3 welded to the casing 1 and a pin-shaped member 4 having a tapered end 4a and joined to said pipe-like member 3, or the fixing means each welded to the casing 1 and having a tapered end 2a, so that said fixing means pierce through said laminate layers with the tapered end 4a or 2a of each said fixing means projecting out from the innermost ceramic fiber layer 6a, and then a ceramic cup-shaped member 5 or a fastening member is secured around the projecting tapered end thereby said laminated ceramic fiber layers 6 are fixed to the casing 1.
Furthermore, blanket type or other type ceramic fiber layers are known. For instance, as illustrated in FIG. 2, a laminate 10 comprising the layer-built ceramic fiber blocks 9 on the furnace wall side and the layer-built ceramic fiber blocks 9a on the inner side of the furnace, each of blocks 9 and 9a being bonded together by an adhesive 8, is pressed against the tapered end 2a of each pin-shaped fixing means 2 which is welded to the casing 1, so that each said pin-shaped fixing means pierces through the laminate 10 with the tapered end 2a of each said fixing means projects out from the laminate 10, and then a metallic fastening member 7 is secured around the projecting tapered end thereby said ceramic fiber blocks 9 and 9a are secured to the casing 1.
In still another known method, as illustrated in FIG. 3, the ceramic fiber layers 6 and another ceramic intermediate layer 11 harder than said ceramic fiber layers 6 are pressed against the metallic pin-shaped fixing means 2 welded to the casing 1 so that said fixing means 2 pierces through said layers 6 and 11 with the other end 2b of each said fixing means 2 projecting out from the intermediate layer 11 and then a metallic fastening member 7 is secured around the projecting end 2b of each said fixing means 2 to fix said ceramic fiber layers 6 and intermediate layer 11 to the casing 1, and then the innermost ceramic fiber layer 6a is fixed to the intermediate layer 11 by the threaded ceramic pins 14 which are screwed into the layers 6 and 11 (at least into the intermediate layer 11) through the innermost ceramic fiber layer 6a.
In these methods, however, the operation of pressing the ceramic fiber layers 6 and 6a or a laminate 10 of ceramic fiber blocks 9 and 9a against the fixing means (comprising pin-shaped members 2, 4 and/or pipe-shaped member 3) to let said fixing means pierce through said layers 6, 6a or said laminate 10 so that the tapered end 2a or 4a or the end 2b of each said fixing means projects out from the innermost ceramic fiber layer 6a or the innermost ceramic fiber block 9a has been quite troublesome and time-consuming. Also, in case of using a ceramic intermediate layer 11, in addition to the troublesome and time-consuming operation for pressing the intermediate layer 11 against the pin-shaped fixing means 2 so that its end 2b projects from said layer 11, there has been also the problem that the ceramic pins 14 could become loose or come off the intermediate layer 11 because of its fragility.